Play Along Speed Stacks Competition Cups Lime Green with Lime Green Bag Add all new colors to your existing Speed Stacks collection. Stack with solid colors, or mix-and-match to make multi colored sets. Now everyone can have their own set of Speed Stacks even if you share a Stack Mat. Comes with all new brightly colored sports carry bags. Speed Stacks Competition Cups are official equipment of the World Sport Stacking Association.